Washing cement from around disconnectible down hole connection

ABSTRACT

After an intercasing string annulus has been cemented to a level above a down hole hanger in the inner string, a sub is partly backed out of an upward extension of the hanger to expose circulating ports having conduits channeling washing fluid to substantially below the sub-to-hanger connection and preferably to the level of the hanger flutes, to provide for disconnection and reconnection of the sub (for temporary abandonment of the well) and for cutting the inner casing below its hang point (for recovery of the string in a permanent abandonment of the well).

United States Patent [72] lnventors John Slack; 3,335,799 8/1967 Miller 166/87 Willis Marvin Phipps, both of Houston, 3,364,996 l/1968 Brown 166/208 Tex. 3,460,615 8/1969 Watkins 166/208 [2]] Appl. No. 876,809 3,489,2l5 l/l970 Regan 166/208 [221 Med 1969 Primary Examiner-James A. Leppink [45] Patented July Alto n -Cushman Darb & Cush an [73] Assignce Gray Tool Company r ey y m Houston, Tex.

[54] WASHING CEMENT FROM AROUND ET LE WNII LE NNETIN m g 0 CO C 0 ABSTRACT: After an intercasing string annulus has been ces, raving igs.

mented to a level above a down hole hanger In the mner string, U-S- a ub is partly backed out of an u ward extension of the l l f Cl F 21b 43/10 hanger to expose circulating ports having conduits channeling Field of starch 166/315, washing fluid to substantially below the sub-tohanger connec- 87 tion and preferably to the level of the hanger flutes, to provide for disconnection and reconnection of the sub (for temporary [56] References cued abandonment of the well) and for cutting the inner casing UNITED STATES PATENTS below its hang point (for recovery of the string in a permanent 3,260,309 7/1966 Brown 166/208 abandonment of the well).

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PATENTEU JUL 619?! /Z5 AF INVENTORS ATTORNEYS PATENIED JUL 6l97l .3, 590.922

sum 6 OF 6 WASHING CEMENT FROM AROUND DISCONNECTIBLE DOWN HOLE CONNECTION BACKGROUND OF THE INVENTION The US. Pat. of Pitts et al., No. 3,405,763, issued Oct. 15, 1968 describes a down hole, pawl-tripped, expansible ringtype casing hanging system substantially as sold by the assignee of that patent, Gray Tool Company of Houston, Tex. as its D.l" line of well completion equipment. (See pages 2l042l07 of Composite Catalog of Oilfield Equipment and Services, l968-69 Edition, Gulf Publishing Houston, Tex.) That well completion apparatus is fairly explicitly described in those publically available documents and so will not be described in such detail here. Suffice it to say here drawing particular attention to FIG. 9b of the Pitts et al. patent that the system provides for hanging an inner string of pipe with respect to an outer string of pipe by means of incorporation of a fluted hanger in the inner string, which seats on a down hole internal shoulder in the bore of the outer string via a bearing ring which is initially stowed in an inactive mode on the hanger, then released for self-expansion through the action ofa pawl-tripping arrangement.

One feature of the DJ equipment which has found acceptance in the marketplace is the provision of an unscrewable joint at the upper end of the hanger, which is for allowing easy recovery of all of the inner string, above the hanger even after cementing, should temporary abandonment and capping of the well be found desirable.

(Temporary abandonment is utilized in the petroleum welldrilling industry al., permit maximum use of equipment during the period of drilling exploration and field or formation definition wells, before a decision has been reached whether there is enough recoverable subterranean petroleum and attendant products to make completion, production, separation and gathering economically feasible.) When a decision is made to complete the abandoned well a threaded or stabbable sub is reconnected to the hanger. This procedure is described in the Pitts et al. patent in relation to FIGS. l0l2 thereof. Additional designs of tie-back subs usable with the "DJ" hangers are illustrated in the US. Pats. of Quebe et al., No. 3,400,950, issued Sept. 10, 1968 and Harwell, .lr., No. 3,456,729, issued July 22, I969, both assigned to Gray Tool Company.

The unscrewable joint referred to above also comes into use during cementing of the interstring annulus since circulating parts for washing out excess cement are provided on the hanger. These may be exposed by partly unthreading the sub from the hanger at said unscrewable joint.

In the cementing operation, cement is forced down the bore of the inner string with a following plug until returns from the intercasing annulus are visible at the surface (i.e. issue from piping connected to that annulus at the surface). Then the cir' culation parts are opened and washing fluid is circulated out the ports and up to the surface for a sufficient period of time (e.g. 2 hours) that the washing fluid is no longer turbid with diluted cement, indicating that the cement in the annulus has been washed out down to the level of the circulating ports and probably to a level somewhat therebelow. However with methods currently in use by most operators it cannot be known with certainty that some cement has not been left above the desired level due to channeling of the washing fluid through the cement. If such cement is left and is allowed to harden, the tie-back sub may be locked in place so it can neither be backed out nor fully reconnected.

SUMMARY OF THE INVENTION In accordance with the present invention the tie-back con nection including a sub, is spaced further above (for instance O-25 feet above) the hanger. After an intercasing string an nulus has been cemented to in level above a down hold hanger in the inner string, a sub is partly backed out of an upward extension of the hanger to expose circulating ports having conduits channeling washing fluid to substantially below the subto-hanger connection and preferably to the level of the hanger flutes, to provide for disconnection and reconnection of the sub (for temporary abandonment of the well) and for cutting the inner casing below its hang point (for recovery of string in a permanent abandonment of the well). In one embodiment the washing fluid conduits are individual pipes; in another, they include a single tube surrounding an upward extension of the hanger. Although the invention is especially well suited for use with equipment as shown in the aforementioned Pitts et al., Quebe et al. and Harwell, Jr. patents, it should be recognized that the principles are applicable to equipment of others design and to equipment evolving from that described in the aforementioned patents.

The principles of the invention will be further hereinafter discussed with reference to the drawings wherein preferred embodiments are shown. The specifics illustrated in the drawings are intended to exemplify, rather than limit, aspects of the invention as defined in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view, with parts broken away and sectioned, of a first down hole petroleum well apparatus illustrating principles of the invention with a fluted, circumferential hanger;

FIG. 2 is a longitudinal sectional view showing a modification of the apparatus of FIG. 1 to cooperate with a snapring hanger;

FIG. 3 is a side elevation view with parts broken away and sectioned, of a further modification of the apparatus to include individual circulating port manifolds;

FIG. 4 is a side elevation view with parts broken away and sectioned, of an illustration of the use of the principles of the invention in a concentrically completed well which has been temporarily abandoned;

FIG. 5 is a longitudinal sectional view of part of a petroleum well illustrating a further embodiment of the apparatus of the invention and FIG. 6 is a fragmentary longitudinal sectional view similar to an upper portion of FIG. 5, but along a plane angularly spaced from that of FIG. 5.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS In the following description particular casing sizes will be referred to in order to quickly impart to the interested, informed reader a complete understanding of the invention. Such readers will understand that the casing sizes are exemplary; other sizes could be employed.

In FIG. 1 there is shown a 20-inch casing string 10 comprising an outer if not the outermost string of casing of a petroleum well, which may be an offshore well drilled from a floating or bottom-supported well-drilling rig. The outer casing string 10 has a hanger seat 12 formed therein at a down hole location (for instance a few feet or hundreds of feet below the mud line if an underwater well). In the instance depicted, the seat 12 is defined on an axially short radially thickened tubular collar 14 welded into the casing string 10 at 16. The seat 12 extends circumferentially of the bore of the collar 14 and faces upwardly.

At the stage depicted in FIG. 1, the well has been drilled further since the emplacement of the outer casing string, and an inner string of l3%-inch casing 18 has been lowered into the well and hung therein upon the seat 12. The inner string 18 incorporates an exteriorly fluted l5%-Xl3%-inch hanger 20, an exteriorly fluted l5%-inch tie-back collar 22 and an intervening space nipple 24. The tie-back collar 22 is depicted (threadably) receiving a lowering sub 26 which is as depicted in the lower right figure on page 2l06 of the aforesaid Composite Catalog. The lowering sub connects with the (unseen) riser ofthe l3%-inch casing string 18.

The tie-back collar 22 through bore 28 includes a tapered seat 30 with which the nose portion 32 of the sub 26 seals to block off the plurality of circulation ports 34 which extend between the bore 28 and the exterior of thecollar 22 above the seat 30. In the instance depicted, the circulation ports 34 are set on axes which radiate obliquely downwardly from the longitudinal axis of the tie-back collar. At and below the location of the emergence of each port 34, the exterior of the collar is milled away or otherwise recessed in an angularly narrow vertical band to provide exterior flutes 36 communicating with the respective ports 34.

The element shown directly seating upon the shoulder 12 is an l8%- l5-inch annular hanger 38 having a plurality of vertical, exterior flutes 40 communication between above and below the exterior hanger shoulder 42 thereof which faces outwardly and downwardly and seats upon the shoulder 12. It should now be noticed that an exterior, downwardly facing circumferential shoulder 44 is provided on the fluted hanger 20, intermediate the ends of the vertical flutes 46 thereon. The shoulder 44 seats on the upper end of the hanger 38. The assembly depicted in FIG. I is completed by a tubular sleeve 48 which is received over the lower end of the tie-back collar 22, spacedlysurrounds the space nipple 24 and is received over the upper end of the hanger 20. The upper end of the sleeve 48 is circumferentially sealed and secured to the tie-back collar 22 above the circulation ports 34 by circumferential welding at 50. The lower end of the sleeve 48 is circumferentially sealed and secured to the upper end of the hanger 38 at a location spaced radially outwardly from the seating of the hanger thereupon, by circumferential welding at 52 above the lower extent of the flutes 46.

The assembly which includes the tie-back collar 22, space nipple 24, fluted hanger 20, fluted hanger 38 and tubular sleeve 48 are by current preference made from the several parts as explained above because, in practice, the assembly can be more economically fabricated from a combination of forgings and tube stock. However, at least some of the parts of this assembly could be made integrally with others of the parts of the assembly.

After the equipment as shown in FIG. I is in place in a well, the annulus 60 between the inner and outer strings of easing may be cementedusing a well-known technique, e.g. wherein a cement slurry is pumped down the bore of the inner string with a wiper plug behind it, the slurry passes out of the lower end of the inner string and up in the annular space between the hole wall and the outside of the inner string, then, further upwardly, filling the annulus 60 between the inner and outer casing strings. To insure that the intercasing annulus is properly cemented, operators may often utilize such an excess of cement that some slurry pours out at the drilling rig from conduits connected to the inner casing annulus 60 at the surface.

The cementing may be alternatively carried out by lowering a small-bore grouting string into the annulus 60 and forcing cement slurry directly into the annulus 60. This method of cementing is also well known.

However, in the instance of using equipment of the DJ type, it is necessary to clear cement from the region of the tie-back collar 22 lowering sub 26 threaded joint, and preferably to below the level of the shoulder 12.

Accordingly, while the cement slurry is still pumpable or dilutable and pumpable, the lowering sub 26 is partly unthreaded from the tie-back collar 22, sufficiently to expose the circulation ports 34 to the base of the inner casing string (see the phantom line partly unthreaded location of the nose of the lowering sub at 26a in FIG. I).

Then, with an inflatable packer or the like bridging the bore of the inner casing string below the level of the ports 34, circulation fluid, e.g. water with the possible addition of commer cially available cement dilution assisting agents, is pumped down the bore of the inner casing string, passing out through the circulation ports 34, down through the flutes 36, down through the annular space between the space nipple 24 and tubular sleeve 48 down and outthrough the flutes 46, outwardly around the lower end of the hanger 38, up the flutes 40, and upwardly through the intercasing annulus 60 to the surface.

Circulation is carried on in this manner until the circulation fluid coming out of the well at the surface is no longer murky with cement and has been running clear for some time, e.g. for an hour or so. Then, if further drilling is to be conducted, the lowering sub 26 is threaded back home to close and seal off the circulation ports and drilling is recommenced down through the bore of the inner string of casing. This may involve further preparatory steps not part of the present invention as will be understood by those skilled in well drilling, such as recovery of packers, drilling or recovery of plugs and changing or installation of blowout preventers for the inner string of casing either at the surface or at a submerged location in the riser above the sub 26.

In any event, the cementing and washing procedures when performed as described above ensure that the annulus 60 area surrounding and above the joint between the tie-back collar and the lowering sub is so free of cement that strong assurance may be had that the joint can be unscrewed. Even if a small amount of cement were left at the level of the joint, the fact that cement has also been removed in the washing process from a further, lower area down to about 64, ensures that the remaining cement can settle down into the lower area and thus assuredly free the joint area of cement. Disconnection at the joint would be needed were it desired to temporarily abandon the well as outlined in the aforementioned Pitts et al. patent. This procedure involves unthreading and pulling all of the lowering subs (if there are several strings) and associated risers and installing abandonment caps over the respective tieback collar upper ends. For permanently abandoning the well, more down hole equipment may be recovered if the casing inner string 18 is cut off below its hang point using commercially available casing cutting equipment.

In the modified embodiment shown in FIG. 2, elements which equate to those as described above in respect to the embodiment shown in FIG. 1 are like numbered, but raised by 100. In the instance depicted, the outer casing is a l3%-inch O.D. casing, the inner casing is a 9%-inch O.D. casing and the hanger I38 is of the pawl-actuated expanded expansible snapring type described in the aforementioned Pitts et al. patent. This hanger, in the instance depicted is not exteriorly fluted (although such could be provided if the remainder of the hanger were strong enough to take the load of the equipment hung and to be hung therefrom), so washing fluid circulates out through that portion of the flutes on theexterior of the hanger 1120 which are exposed below the lower end of the tubular sleeve 148 and above the upper end of the snapring hanger 138. Circulation of washing fluid is in the direction of the arrows provided on the FIG.

A further modification of the FIG. 1 structure is depicted in FIG. 3 wherein 200 has been added to the numerals designating corresponding parts.

The FIG. 3 construction differs from that shown in FIG. 1 by a plurality (for instance four equiangularly spaced) radially directed circulation ports 234 which feed individual elbows 236 welded at 250 to the exterior of the tie-back collar. A small-diameter pipe 248 extends vertically downwardly from the vertically downwardly directed outer leg of each elbow 236 and terminates with open end in an exterior flute of the unitary hanger 220/238. Washing fluid issuing from the individual pipe open ends circulates downwardly in the flutes 246 and up the flutes 240 located angularly between the flutes 246 as depicted in the arrows on FIG. 3.

Intermediate their vertical extent the individual pipes 248 pass over and are braced by an annular band 270 to which each is welded at 272. The band 270 encircles the space nipple 224.

A temporarily abandoned well is shown in FIG. 4 after two successive, concentric inner strings (A and B) have been installed, cemented and had their joints circulated free in accordance with the embodiment of FIG. 3, and wherein an innermost casing string and tubing are shown having been subsequently installed. (These latter are normally not cemented, at least not up to the level of the respective hangers.) The well is depicted having been temporarily abandoned by unthread ing and withdrawing of the respective lowering nipples and risers thereabove and the installing of abandonment caps 280. If it should be desired to tie back into the well of HO. 4, this may be done by removing the abandonment caps and by threading tie-back subs (e.g. identical to the aforementioned US. Pat. of Quebe et al. No. 3,400,950) and completing the well in accordance with approved practices.

A variation of the FIG. 3 equipment is depicted in FIGS. 5 and 6, corresponding parts being similarly numbered, but raised by 300 from the system used in connection with FIG. 1.

In the FIGS. 5 and 6 embodiment, the individual wash pipes 348 terminate above the flutes 346 of the unitary hanger 320/338 and the vertical flutes 340 for upward circulation are provided intermediate the radial extent of the internal hanger seat member of the outer casing string (which in the instance depicted is a 36-inch drivepipe, the outermost string of casing in the underwater well). Circulation of washing fluid proceeds in the direction of the arrows on FIG. 5. It should be apparent that the individual wash pipes could extend down into the flutes 346 in this embodiment. it should further be noted that upward circulation of washing fluid from below the inner casing string of outer casing string hanger could in the embodiments of FIGS. 1-4 be promoted by providing flutes or equivalent passageways through the outer casing string internal hanger seat member, as shown in FIG. 5.

As a further difference from what is illustrated in the earlier Figures, it should be noted that the elbows 336 are incorporated in a hollow annular member 378 in which a circumferential radially inwardly opening groove 380 accepts the washing fluid from the circulation ports 334 and distributes it to the separate vertical legs of the elbows 336 and the wash pipes 348.

in the FIGS. 5 and 6 apparent that the unit 378 and a wash pipes mounting ring 382 adjacent the lower ends of wash pipes are secured by setscrews 350 rather than by welding to the tieback collar and circumferential sealing rings 384, 386 received in the unit 378 above and below the groove 380 seal the groove 380 with respect to the exterior of the tie-back collar enclosing the circulation ports 334. This manner of securement and sealing is, for lower-pressure usage, an alternative to the weldments depicted in the FIGS. 1-4 embodiments.

lt should now be apparent that the washing cement from around disconnectable down hole connection as described herein above possesses each of the attributes set forth in the specification under the heading Summary of the Invention" hereinbefore. Because the washing cement from around disconnectable down hold connection of the invention can be modified to some extent without departing from the principles of the invention as they have been outlined and explained in this specification, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the following claims.

What we claim is:

1. For incorporation intermediate a string of inner casing to be hung with respect to an outer string of casing of a petroleum well wherein the intercasing annulus is to be at least partly filled with a pumpable material such as an hydraulic cement slurry, then an upper portion of said pumpable material removed by circulating a washing fluid, a well completion equipment assembly including:

a tubular hanger body having means defining a downwardly facing exterior shoulder thereon; means defining at least downward circulation flute on said hanger body communicating between the exterior of said hanger body above said shoulder, at an inlet of said downward circulation flute, and the exterior of said hanger body below said shoulder, at an outlet of said downward circulation flute;

means defining at least one upward circulation flute on said hanger body communicating between a location adjacent the outlet of said at lest one downward circulation flute, at an inlet of said upward circulation flute, and the exterior of said hanger body above said shoulder, at an outlet of said upward circulation flute;

tubular conduit means extending coaxially upwardly from said hanger body in sealed communication with the bore of said hanger body, said tubular conduit means including a tubular tie-back collar spaced axially above said exterior shoulder of said hanger body;

means defining at least one circulation port extending laterally through said tie-back collar for communicating the bore thereof with the exterior thereof;

closure means for selectively blinding and opening said at least one circulation port;

and wash pipe conduit means having one end thereof communicated to the at least one circulation port to receive wash fluid exiting from said tie-back collar bore through said at least one circulation port, and having the opposite end thereof disposed adjacent said inlet of said at least one downward circulation flute for directing the received wash fluid downwardly into said at least one downward circulation flute, whereupon said wash fluid may pass out of the outlet of said at least one downward circulation flute, into the inlet of said at least one upward circulation flute and out of the outlet of said at least one upward circulation flute.

2. The assembly of claim 1 wherein the vertical separation of said at least one circulation port and said downwardly facing exterior shoulder is at least 6 feet.

3. The assembly of claim 1 wherein said wash pipe conduit means comprises a tubular sleeve spacedly surrounding said tubular conduit means, being sealingly circumferentially secured to said tie-back collar above said at least one circulation port, and being sealingly circumferentially secured to said hanger body radially intermediate the extent of the hanger body.

4. The assembly of claim 3 wherein said tie-back collar includes means defining at least one flute in the exterior thereof said at least one flute extending downwardly from communication with said at least one circulation port.

5. The assembly of claim 1 wherein said wash pipe conduit means comprises:

elbow means having a horizontally directed leg connected to said at least one circulation port and a vertically downwardly directed leg, and a vertical wash pipe having an open lower end and an upper end connected to said elbow vertically downwardly directed leg.

6. The assembly of claim 5 wherein said wash pipe open lower end is disposed within said at least one downward circulation flute.

7. The assembly of claim 6 wherein said at least one downward circulation flute and said at least one upward circulation flute are disposed angularly spacedly adjacent one another.

8. The assembly of claim 5 wherein said at least one circulation port is provided by a plurality of angularly spaced circulation ports; wherein said at least one downward circulation flute is provided by a plurality of angularly spaced downward circulation flutes; and wherein said at least one upward circulation flute is provided by a plurality of angularly spaced upward circulation flutes; said wash pipe conduit means comprising a said elbow means and a said vertical wash pipe connected thereto for each circulation port; securement means carried on said tubular conduit means near the lower ends of the wash pipes bracing each wash pipe with respect to said tubular conduit means.

9. The assembly of claim 8 further comprising an annular manifold interconnecting all of said circulation ports and all of said elbow means horizontally directed legs.

10. The assembly of claim 1 wherein said hanger body includes an expansible split-ring-type hanger, said downwardly facing exterior shoulder being defined by a lower end surface of said split-ring type hanger.

1!. For incorporation intermediate a string of inner casing to be hung with respect to an outer string of easing of a petroleum well wherein the intercasing annulus is to be at least partly filled with a pumpable material such as an hydraulic cement slurry, then an upper portion of said pumpable material removed by circulating a washing fluid, a well completion equipment assembly including:

tubular hanger body having means defining a downwardly facing exterior shoulder thereon; means defining at least one downward circulation flute on said hanger body communicating between the exterior of said hanger body above said shoulder, at an inlet of said downward circulation flute, and the exterior of said hanger body below said shoulder, at an outlet of said downward circulation flute;

a tubular outer casing string hanger seat member having means defining a radially inwardly protruding, upwardly facing shoulder in the bore thereof configured to support said hanger body via said downwardly facing exterior shoulder of said hanger body;

means defining at least one upward circulation flute in said tubular outer casing string hanger seat member communicating between the bore of said member below said upwardly facing shoulder at an inlet of said at least one upward circulation flute and the bore of said member above said upwardly facing shoulder at an outlet of said at least one upward circulation flute;

tubular conduit means extending coaxially upwardly from said hanger body in sealed communication with the bore of said hanger body, aid tubular conduit means including a tubular tie-back collar spaced axially above said exterior shoulder of said hanger body;

means defining at least one circulation port extending laterally through said tie-back collar for communicating the bore thereof with the exterior thereof;

closure means for selectively blinding and opening said at least one circulation port;

and wash pipe conduit means having one end thereof communicated to the at least one circulation port to receive wash fluid exiting from said tie-back collar bore through said at least one circulation port, and having the opposite end thereof disposed adjacent said inlet of said at least one downward circulation flute for directing the received wash fluid downwardly into said at least one downward circulation flute, whereupon said wash fluid may pass out of the outlet of said at least one downward circulation flute, into the inlet of said at least one upward circulation flute and out of the outlet of said at least one upward circulation flute. 

1. For incorporation intermediate a string of inner casing to be hung with respect to an outer string of casing of a petroleum well wherein the intercasing annulus is to be at least partly filled with a pumpable material such as an hydraulic cement slurry, then an upper portion of said pumpable material removed by circulating a washing fluid, a well completion equipment assembly including: a tubular hanger body having means defining a downwardly facing exterior shoulder thereon; means defining at least downward circulation flute on said hanger body communicating between the exterior of said hanger body above said shoulder, at an inlet of said downward circulation flute, and the exterior of said hanger body below said shoulder, at an outlet of said downward circulation flute; means defining at least one upward circulation flute on said hanger body communicating between a location adjacent the outlet of said at lest one downward circulation flute, at an inlet of said upward circulation flute, and the exterior of said hanger body above said shoulder, at an outlet of said upward circulation flute; tubular conduit means extending coaxially upwardly from said hanger body in sealed communication with the bore of said hanger body, said tubular conduit means including a tubular tie-back collar spaced axially above said exterior shoulder of said hanger body; means defining at least one circulation port extending laterally through said tie-back collar for communicating the bore thereof with the exterior thereof; closure means for selectively blinding and opening said at least one circulation port; and wash pipe conduit means having one end thereof communicated to the at least one circulation port to receive wash fluid exiting from said tie-back collar bore through said at least one circulation port, and having the opposite end thereof disposed adjacent said inlet of said at least one downward circulation flute for directing the received wash fluid downwardly into said at least one downward circulation flute, whereupon said wash fluid may pass out of the outlet of said at least one downward circulation flute, into the inlet of said at least one upward circulation flute and out of the outlet of said at least one upward circulation flute.
 2. The assembly of claim 1 wherein the vertical separation of said at least one circulation port and said downwardly facing exterior shoulder is at least 6 feet.
 3. The assembly of claim 1 wherein said wash pipe conduit means comprises a tubular sleeve spacedly surrounding said tubular conduit means, being sealingly circumferentially secured to said tie-back collar above said at least one circulation port, and being sealingly circumferentially secured to said hanger body radially intermediate the extent of the hanger body.
 4. The assembly of claim 3 wherein said tie-back collar includes means defining at least one flute in the exterior thereof said at least one flute extending downwardly from communIcation with said at least one circulation port.
 5. The assembly of claim 1 wherein said wash pipe conduit means comprises: elbow means having a horizontally directed leg connected to said at least one circulation port and a vertically downwardly directed leg, and a vertical wash pipe having an open lower end and an upper end connected to said elbow vertically downwardly directed leg.
 6. The assembly of claim 5 wherein said wash pipe open lower end is disposed within said at least one downward circulation flute.
 7. The assembly of claim 6 wherein said at least one downward circulation flute and said at least one upward circulation flute are disposed angularly spacedly adjacent one another.
 8. The assembly of claim 5 wherein said at least one circulation port is provided by a plurality of angularly spaced circulation ports; wherein said at least one downward circulation flute is provided by a plurality of angularly spaced downward circulation flutes; and wherein said at least one upward circulation flute is provided by a plurality of angularly spaced upward circulation flutes; said wash pipe conduit means comprising a said elbow means and a said vertical wash pipe connected thereto for each circulation port; securement means carried on said tubular conduit means near the lower ends of the wash pipes bracing each wash pipe with respect to said tubular conduit means.
 9. The assembly of claim 8 further comprising an annular manifold interconnecting all of said circulation ports and all of said elbow means horizontally directed legs.
 10. The assembly of claim 1 wherein said hanger body includes an expansible split-ring-type hanger, said downwardly facing exterior shoulder being defined by a lower end surface of said split-ring-type hanger.
 11. For incorporation intermediate a string of inner casing to be hung with respect to an outer string of casing of a petroleum well wherein the intercasing annulus is to be at least partly filled with a pumpable material such as an hydraulic cement slurry, then an upper portion of said pumpable material removed by circulating a washing fluid, a well completion equipment assembly including: tubular hanger body having means defining a downwardly facing exterior shoulder thereon; means defining at least one downward circulation flute on said hanger body communicating between the exterior of said hanger body above said shoulder, at an inlet of said downward circulation flute, and the exterior of said hanger body below said shoulder, at an outlet of said downward circulation flute; a tubular outer casing string hanger seat member having means defining a radially inwardly protruding, upwardly facing shoulder in the bore thereof configured to support said hanger body via said downwardly facing exterior shoulder of said hanger body; means defining at least one upward circulation flute in said tubular outer casing string hanger seat member communicating between the bore of said member below said upwardly facing shoulder at an inlet of said at least one upward circulation flute and the bore of said member above said upwardly facing shoulder at an outlet of said at least one upward circulation flute; tubular conduit means extending coaxially upwardly from said hanger body in sealed communication with the bore of said hanger body, aid tubular conduit means including a tubular tie-back collar spaced axially above said exterior shoulder of said hanger body; means defining at least one circulation port extending laterally through said tie-back collar for communicating the bore thereof with the exterior thereof; closure means for selectively blinding and opening said at least one circulation port; and wash pipe conduit means having one end thereof communicated to the at least one circulation port to receive wash fluid exiting from said tie-back collar bore through said at least one circulation port, and having the opposite end thereof disposed adjacent said inlet of said at least one downward circulAtion flute for directing the received wash fluid downwardly into said at least one downward circulation flute, whereupon said wash fluid may pass out of the outlet of said at least one downward circulation flute, into the inlet of said at least one upward circulation flute and out of the outlet of said at least one upward circulation flute. 